TextureBrush bgimgBruch = new TextureBrush(m_bgImage);
            GraphicsPath bgimgPath = new GraphicsPath();
            Region eRegion = null;

//.....  eRegion 在这里创建， 并执行了多次Uinon（超过600次）操作。

            System.Diagnostics.Stopwatch timer2 = new System.Diagnostics.Stopwatch();//new一个stopwatch
            timer2.Start();
            g.FillRegion(bgimgBruch, eRegion);
            timer2.Stop();

            FileLog.WriteInfo("Draw(Graphics g) ", "Region Spend time: " + timer.ElapsedMilliseconds.ToString() + " FillRegion Spend time: " + timer2.ElapsedMilliseconds.ToString());